The Entry Capacity Substitution Methodology Statement

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Issue 5.26.1 Revision Informal Consultation Draft The Entry Substitution Methodology Statement Effective from 2 nd February1 st September 2015 Page 1 of 31

ENTRY CAPACITY SUBSTITUTION METHODOLOGY STATEMENT Document Revision History Version/ Revision Number Date of Issue Notes 0.1 17 May 2007 Draft for consultation 0.2 4 July 2008 Revised draft updated following Substitution Workshops. Issued as a discussion document. 0.3 15 May 2009 Informal consultation Major changes to reflect workshop output. 0.3C 15 May 2009 Drafted for Option Approach 0.4 24 July 2009 Further detail added for formal consultation. 0.5 7 September 2009 Revised following comments received to formal consultation. Scope for refund of retainer charges extended to allow capacity allocated at Y+5 and Y+6 to trigger refund. Retainer requests to be acknowledged. Individual User retainers granted to be notified to the relevant User. Full and partial refunds of retainer charges will now be made in the year they are triggered. Revisions to zones will now be notified before the retainer window. Minor amendments to aid clarity. 1.0 8 December 2009 V0.5 approved by the Authority. 1.1 6 August 2010 Annual Review Consultation Draft 1.2 23 September 2010 Revision to appendix 1 following comments received to formal consultation. Submitted for Approval 2.0 21 October 2010 Authority Approval 2.1 04 August 2011 Annual review Consultation Draft 2.2 14 September 2011 Correction to footnote to appendix 1 changed from the QSEC invitation letter to the Retainer invitation letter. Submitted for Approval 3.0 12 October 2011 Authority Approval 3.1 28th September 2012 Annual Review Consultation Draft. 3.2 9 November 2012 No further changes following consultation. Submitted for Approval 4.0 5 TH December 2012 Authority Approval Page 2 of 31

4.1 June 2013 Updated for RIIO-T1 New terminology and Licence references 4.2 September 2013 Minor amendments to correct editing issues and improve clarity. Paragraph 87 added: Facilitates possible veto of substitution proposals at Interconnection Points. Submitted for Approval. Submitted for Approval 5.0 October 2013 Authority Approval 5.1 September 2013 Annual Review (informal consultation) Updated to align to Modification 0452: Introduction of the Planning and Advanced Reservation Agreement (PARCA) Annual Review (formal consultation) Minor updates following informal consultation. 5.2 December 2014 Further review to align to Modification 0465V: Introduction of the Planning and Advanced Reservation Agreement (PARCA), Weighted Average PARCA Security and the revised Licence arrangement. Footnote 7 added to recognise the potential implementation of UNC Modification 0501, 0501A, 0501B or 0501C. 5.3 [Submitted for approval] To be confirmed 6.0 [Authority Approval] To be confirmed Page 3 of 31

Informal consultation Clarifications arising from development of EU Modifications: 6.1 December 2014 0500: EU Regulations - Allocation Mechanisms with Congestion Management Procedures and 0501: Treatment of Existing Entry Rights at the Bacton ASEP to comply with EU Regulations or 0501A: Treatment of Existing Entry Rights at the Bacton ASEP to comply with EU Regulations, including capacity return option or 0501B: Treatment of Existing Entry Rights at the Bacton ASEP to comply with EU Regulations, including a restricted capacity return option or 0501C: Treatment of Existing Entry Rights at the Bacton ASEP to comply with EU Regulations, including a capped capacity return option and an aggregate overrun regime and the draft revised licence arrangement Page 4 of 31

ABOUT THIS STATEMENT This Entry Substitution Methodology Statement (the Statement ) 1 describes the methodology that National Grid Gas plc ( National Grid ) in its role as holder of the Gas Transporter Licence in respect of the NTS 2 ( the Licence ) will utilise to determine proposals for Entry Substitution, i.e: the substitution of unsold Non-incremental Obligated Entry 3 from one Aggregate System Entry Point ( ASEP ) 4 to another ASEP in response to demand for Incremental Obligated Entry. In particular, it defines: under what circumstances National Grid will consider such substitutions; and the process to be undertaken by National Grid to determine its proposals to substitute capacity and revise baseline quantities. This Statement is one of a suite of documents that describe the release of NTS capacity by National Grid and the methodologies behind them. The other documents are available on the National Grid website at: http://www2.nationalgrid.com/uk/industry-information/gas-capacity-methodologies/ This Statement is effective from 2 nd February1st September 2015. This Statement contains terminology relating to entry capacity which is used in the Licence and in the Uniform Network Code ( UNC ). Licence defined capacity terms are given in bold italics; UNC defined capacity terms appear in bold. Other defined terms used but not defined in this Statement shall have the meaning given to them in the UNC and/or Licence as appropriate. It should be noted that this Statement does not provide the methodology by which, and from when, Entry will be made available. The processes for Shipper Users to obtain, and for National Grid to release Entry can be found in the UNC) and the Entry Release Methodology Statement ( ECR ). This Statement applies in respect of Incremental Obligated Entry, released as a result of valid bids for Quarterly NTS Entry made in accordance with the UNC and the ECR. The timing of the release of any Incremental Obligated Entry will be in accordance with the ECR. Where such Incremental Obligated Entry is to be made available as a result of Entry Substitution, capacity will be made available from a date consistent with this Statement. If you require further details about any of the information contained within this Statement or have comments on how this Statement might be improved please contact our Gas Charging and Development team at box.transmissioncapacityandcharging@nationalgrid.com or at: Gas Charging and Development Transmission Network Service National Grid House Warwick Technology Park Gallows Hill 1 This Statement is often abbreviated to the ECS. 2 The gas National Transmission System 3 For the avoidance of doubt, references to Obligated Entry can be taken to also mean Technical Interconnection Point where it regards Interconnection Point ASEPs. 4 For the purpose of this Statement, references to ASEPs can be taken to also include Interconnection Point ASEPs (IP ASEPs) where it regards consideration as a donor ASEP. Page 5 of 31

Warwick CV34 6DA Page 6 of 31

Contents ABOUT THIS STATEMENT 45 GENERAL INTRODUCTION 68 Background 68 Terminology 68 National Grid s Licence Obligations 710 CHAPTER 1: PRINCIPLES 1012 Purpose of the Methodology Statement 1012 CHAPTER 2: METHODOLOGY 1113 Introduction 1113 Retainers 1416 Retainer Windows 1518 Provision of Retained Information 1518 Retention Charges 1619 Retention Charge Refunds 1619 Allocations 1720 Application of Zones 1922 Recipient ASEP Order 1922 Donor ASEP Order 2023 Network Analysis for Substitution 2023 Substitution Analysis (see Appendix 2) 2124 Partial Substitution 2225 Analysis Output 2225 APPENDIX 1: ENTRY CAPACITY ZONES 2427 APPENDIX 2: PROCESS FOR SUBSTITUTION ANALYSIS 2629 APPENDIX 3: PARCA SUPPORTING INFORMATION 2730 Page 7 of 31

GENERAL INTRODUCTION Background National Grid is the owner and the operator of the gas National 1. Transmission System (NTS) in Great Britain. The NTS plays an important role in facilitating the competitive2. gas market and helping to provide the UK with a secure gas supply. It is a network of pipelines, presently operated at pressures of up to 94 barg, which transports gas safely and efficiently from coastal terminals and storage facilities to exit points from the system. Exit points are predominantly connections to Distribution Networks ( DNs ), but also include storage sites, and direct connections to power stations, large industrial consumers and other systems, such as interconnectors to other countries. These operations are carried out to meet the needs of the companies 3. that supply gas to domestic, commercial and industrial consumers and to power stations. This Statement sets out the methodology that applies for the4. substitution of Substitutable (as defined in paragraph 22) from one or more donor ASEPs to meet demand for Incremental Obligated Entry (i.e. capacity to be made available above the prevailing level of Obligated Entry ) at other ASEPs, in response to signals received from Shipper Users through processes described in the UNC), thereby reducing the need for investment to meet that incremental demand for Entry. The methodology is applicable in respect of capacity released in the long-term 5, i.e. in the Quarterly System Entry ( QSEC ) auctions or pursuant to a PARCA 36. The methodology for moving Entry between ASEPs 5. in the short-term can be found in the Entry Transfer and Trade Methodology Statement. Related processes have been introduced to the UNC. Details of National Grid and its activities can be found on its internet 6. site at www2.nationalgrid.com. An electronic version of this Statement, along with the other related statements can be found on the following web page: http://www2.nationalgrid.com/uk/industry-information/gas-capacity-methodologies/ Entry--Substitution-Methodology-Statement/. Terminology This Statement contains terminology relating to Entry 7. which is used in the Licence for the purposes of distinguishing between National Grid s capacity obligations and revenue treatments. It should be noted that although this terminology exists, it does not change the capacity products that Shipper Users 5 The Incremental element of EU Regulation 984/2013, otherwise known as the code on Allocation Mechanisms (CAM), is under development. There will be no Incremental Obligated Entry release at Interconnection Points once CAM is implemented until development of the Incremental element is complete and implemented meaning that there is currently no way to trigger substitution to an IP ASEP. For the avoidance of doubt, Technical Interconnection Point will still be considered as Substitutable subject to paragraph 89. 36 A PARCA, a Planning and Advanced Reservation of Agreement is a bilateral agreement which allows non-code parties (Reservation Parties) or Users (Reservation Users) to reserve Quarterly NTS Entry and / or Enduring Annual NTS Exit (Flat) ahead of its registration to the User or, as the case maybe, a Nominated User (nominated by the Reservation Party). Page 8 of 31

procure through established UNC processes e.g. Firm NTS Entry and Interruptible NTS Entry. The terminology and relationships relating to Firm Entry 8. are provided below to assist the reader in interpreting this Statement. National Grid has an obligation to release Firm Entry Released at National Grid s discretion Existing Obligated Entry Non-obligated Entry Non-incremental Obligated Entry Incremental Obligated Entry New Incremental Obligated Entry release Subject to Authority Approval Legacy TO Entry Licence Baseline Entry Released after 1st April 2013 Released after 1st April 2013 Released before 1 st April 2013 Trigger for Entry Substitution. Funded Incremental Obligated Entry Legacy Incremental Entry Substitution of unsold capacity between ASEPs. Subject to Authority Approval Reclassification as Non-incremental Obligated Entry at date defined in the Licence The actual definitions of these terms are contained within the9. Licence. Where any conflict arises between the Licence and this Statement the Licence shall prevail. 10. Entry Substitution is therefore, the process of assigning Non-incremental Obligated Entry from one or more ASEP(s) to meet the requirement for Incremental Obligated Entry elsewhere. The substituted Entry is assigned to the ASEP where additional capacity is demanded, in preference to creating additional capacity (Funded Incremental Obligated Entry ) which may require investment in new infrastructure. The Non-incremental Obligated Entry at an ASEP is made up of Licence Baseline Entry as set out in the Licence for the ASEP plus any Legacy TO Entry. The baseline is adjusted, plus (or minus), for any Entry that has been substituted to (or from) the ASEP. In addition, any Funded Incremental Obligated Entry that has been released pursuant to long term auctions held after 1 st April 2013 will be treated as Non-incremental Obligated Entry (Licence Baseline Entry ) five years after this capacity is first released. Any incremental capacity that has been released pursuant to long term auctions held before 1 st April 2013 will also be treated as Non-incremental Page 9 of 31

Obligated Entry (Legacy TO Entry ) from dates defined in Table 8 of Special Condition 5F of the Licence. National Grid s Licence Obligations 11. New and existing Shipper Users of the NTS are able to request to purchase NTS Entry products defined in the UNC for any ASEP defined in the Licence. Such capacity requests will be considered against the provisions of National Grid s statutory and Licence obligations and in accordance with its published methodologies. Overriding obligations applicable to this Statement are set out 12. in the Gas Act and the Licence. Specific obligations in respect of the release of Entry 13. and relevant to this Statement are set out in Special Condition 9B of the Licence. Under this condition, National Grid must prepare a capacity release methodology statement (the ECR ) setting out the methodology by which National Grid will determine whether to make Entry available for sale. The current ECR can be found on National Grid s website. Specific obligations in respect of the substitution of Entry 14. and applicable to this Statement are set out in Special Condition 9A of the Licence and are: 5(a) ensuring that..entry Substitution.is effected ina. a manner consistent with National Grid s duties under the Act and, in particular, the duty to develop and maintain an efficient and economical pipeline system and its obligations under the Licence 5(b) (i) in so far as is consistent with 5(a), to ensure that Entry b. Substitution is effected in a manner which seeks to minimise the reasonably expected costs associated with Funded Incremental Obligated Entry, taking into account the Entry that Shippers have indicated that they will require in the future through making a financial commitment to National Grid. Special Condition 9A also sets out the capacity objectives that 15. the methodologies should seek to meet. In addition to the criteria in paragraph 14 these objectives are: o 5(c) in so far as is consistent with 5(a) to ensure that Entry Substitution, is effected in a manner which is compatible with the physical capability of the NTS; o 5(d) in so far as is consistent with 5(a) to avoid material increases in costs including: Entry and Exit Constraint Management costs in respect of Obligated Entry previously allocated by the Licensee to Relevant Shippers; that are reasonably expected to be incurred by the Licensee as a result of Entry Substitution; o 5(e) in so far as is consistent with 5(a) to facilitate effective competition between relevant Shippers. This Statement has been produced to meet the requirements16. of Special Condition 9A of the Licence in respect of the preparation of Methodology Statements setting out the methodologies by which National Grid will determine its proposals for the substitution of Non-incremental Obligated Entry pursuant to the obligation in paragraph 2(a) of the above stated condition. National Grid believes the Page 10 of 31

content is consistent with its duties under the Gas Act and is consistent with the Licence. National Grid will, through entry capacity substitution: o Make additional Obligated Entry available at the recipient ASEP; and o Reduce the quantity of Obligated Entry available at the donor ASEP in quantities determined in accordance with this Statement. The obligation to provide Entry at the donor ASEP is reduced by the quantity determined, and such substituted capacity will not be available for sale in future auctions at the donor ASEP. This will be achieved by moving unsold Non-incremental Entry from one or more ASEPs to meet the demand for Incremental Obligated Entry at another ASEP in order to minimise the need for Funded Incremental Obligated Entry. The methodology encompasses this obligation and National Grid s wider obligations to develop and maintain an efficient and economic system. Page 11 of 31

CHAPTER 1: PRINCIPLES Purpose of the Methodology Statement The methodology detailed in this Statement is intended to promote 17. the economic and efficient development of the NTS. For the purposes of this methodology this objective is achieved by seeking to minimise the amount of investment that is required to satisfy incremental demand for Entry. Specifically, the methodology describes how capacity could be identified as suitable for substitution froma) locations where there is no long term demand for capacity (as defined by the availability of Non-incremental Obligated Entry that has not been sold, or reserved pursuant to a PARCA, and by the absence of retainers 47 ) to other locations where Funded Incremental Obligated Entry would otherwise be required to be released as a result of accepted bids for Incremental NTS Entry made in long term auctions or to satisfy request for capacity through a PARCA. Subject to the further provisions of this Statement, any available unsold Non-incremental Obligated Entry that is not allocated, or reserved, or subject to a retainer, will be deemed available for substitution. The methodology described in this Statement seeks to ensure 18. that the NTS is efficiently sized by avoiding or minimising investments by the development of proposals for consideration by the Authority to substitute Non-incremental Obligated Entry levels. This may occur under the following circumstances: a) where Shipper Users at an ASEP have requested additional Firm NTS Entry b) where PARCA Applicants at an ASEP have requested additional Firm NTS Entry pursuant to a PARCA in accordance with UNC processes that in aggregate exceed the existing Obligated Entry level, National Grid will consider whether it would be efficient and economic to seek to release the additional Entry required at that ASEP by the substitution of unsold Non-incremental Obligated Entry from other ASEPs. This is described in Chapter 2; Consistent with the Licence and UNC, NTS Entry is 19. a commercial right that may be offered on a daily basis or in, monthly or quarterly multiples thereof; it does not reflect a commitment or obligation upon National Grid to undertake any investment on its network, including, but not limited to the provision of a physical connection to the NTS. 47 Retainers provide Users with an alternative to buying capacity in order to prevent capacity from being substituted away from an ASEP and are defined in detail below, particularly in the section Retainers. Page 12 of 31

CHAPTER 2: METHODOLOGY Introduction This section explains the step by step approach that National20. Grid will undertake in order to develop proposals for submission to, and approval by, the Authority to reduce the level of Non-incremental Obligated Entry at one or more ASEPs to facilitate an increase to the level of Non-incremental Obligated Entry elsewhere so as to avoid the need to release Funded Incremental Obligated Entry and hence to minimise the need for investment in the NTS. Before application of the methodology set out in this Statement 21. demand for Incremental Obligated Entry must satisfy the tests for release of Incremental Obligated Entry as set out in the ECR. In applying the methodology for substitution set out in this Statement 22. the following rules will be applied to determine the quantity of Entry that will be made available for substitution, the Substitutable. Subject to the following rules, Substitutable at an ASEP shall be equal to the unsold quantity of Non-incremental Obligated Entry (as defined in the Licence): that is not offered for release in the QSEC auctions, i.e. a) capacity that is held-back for MSEC auctions will not be available for substitution between ASEPs. Currently this is 10% of Non-incremental Obligated Entry at each ASEP. Hence the Substitutable at an ASEP will be equal to 90% Non-incremental Obligated Entry subject to the following adjustments, c) to k). b) c) that is not offered for release in the Annual Yearly auctions 8, i.e. capacity that is held-back for Annual Quarterly Auctions will not be available for substitution between ASEPs. Currently this is 10% of Technical Interconnection Point at each IP ASEP with respect to Yearly Interconnection Point for gas years Y+1 to Y+5 and 20% for Yearly Interconnection Point for gas years Y+6 to Y+15. Hence the Substitutable at an IP ASEP will be equal to 80% of the Technical Interconnection Point subject to the following adjustments, c) to k). b) currently reserved under a PARCA will not be Substitutable. Where a PARCA is terminated prior to the allocation of capacity, the Reserved Entry may become Substitutable if that capacity is Non-incremental Obligated Entry 59. Where the Reserved Entry is from a different ASEP to where the PARCA has indicated the need for additional capacity (i.e. reserved pending substitution), the Reserved Entry will revert to Substitutable at the donor ASEP if it is no longer required to satisfy a PARCA. 8 The Annual Yearly Auctions and Annual Quarterly Auctions are applicable at Interconnection Points only. 59 This previously reserved capacity will also be available for reservation pursuant to another PARCA (if any) and/or allocation to Users through other auction mechanisms. Page 13 of 31

d) e) f) g) h) i) j) c) that has previously been substituted from an ASEP (i.e. from a donor ASEP) will not be available as Substitutable in respect of the donor ASEP. d) Except where the further provisions of this paragraph 22 apply, capacity that has previously been substituted to an ASEP will be Substitutable from the date where future quantities of that capacity are unsold, are not reserved, and are not retained, at that recipient ASEP. e) Subject to the further provisions of this paragraph, any Funded Incremental Obligated Entry released as a result of QSEC auctions held from 1 April 2013 onwards will not be Substitutable until after a period of five years has elapsed from the initial release date (when it is re-classed as Licence Baseline Entry for the purposes of capacity release obligations). Where Incremental Obligated Entry release is profiled, this will apply to each tranche of capacity. The 10% held back for shorter term auctions applies to this type of capacity from the date of re-classification. f) Subject to the further provisions of this paragraph, any Incremental Obligated Entry released as a result of QSEC auctions held prior to 1 April 2013 (i.e. Legacy Incremental Entry ) will not be Substitutable until the date specified in the Licence (when it is re-classed as Legacy TO Entry for the purposes of capacity release obligations). Where Incremental Obligated Entry release was profiled, this will apply to each tranche of capacity. The 10% held back for shorter term auctions applies to this type of capacity from the date of re-classification. g) allocated in previous QSEC or Annual Yearly auctions will not be Substitutable. allocated in previous QSEC auctions, or reserved pursuant to a PARCA, will be assumed to have been allocated or reserved in the sequence Licence Baseline Entry first, followed by Incremental Entry. This means that capacity available for substitution at ASEPs where incremental capacity signals have previously been seen is likely to be limited (for at least the first five years from the initial release date). h) Any Non-incremental Obligated Entry that is unsold after 1 st October Y+4 610 is Substitutable with respect to demand signalled either via a QSEC Auction or via a PARCA 711. For clarity unsold capacity does not include Reserved Entry and the Y is the year where either has been bid for or capacity has been first reserved via a PARCA. i) Sub-paragraphparagraphs a) limitsand c) limit Substitutable to 90% of the Non-incremental Obligated Entry quantity (10% being held back for MSEC auctions); or in the case of IP ASEPs 80% of Technical Interconnection Point ; plus or minus any quantities identified in sub-paragraphs bc), to gh) and minus any capacity sold. This Statement 610 References in this document to years Y+4 etc relate to capacity years, i.e. year Y is the year of the relevant auction bid or the year of reservation via a PARCA. E.g. for a March QSEC in year Y (2015) capacity release would be October 2018 to September 2019 (Y+4). 711 Subject to the implementation of UNC Modification 501, 501A, 501B or 501C, if implemented, from the end of the March 2015 QSEC allocation process until 31 st October 2015, unsold Non-incremental Obligated Entry at the existing Bacton ASEP will not be considered as Substitutable. Page 14 of 31

incorporates a mechanism that allows Shipper Users to take out a retainer that would reduce the quantity of Substitutable by placing an additional restriction on the availability of capacity for substitution. Further details are given in the Retainers section below. k) j) For each ASEP the quantity of Substitutable will be the lowest value, determined in accordance with this paragraph, for any quarter following the default lead time 812 for the release of Incremental Entry. Irrespective of the date of release of Incremental Entry (which may be later than the default period) capacity will not be substituted from an ASEP in quantities greater than the Substitutable. This is illustrated in Diagram 1 below.. Diagram 1: Substitutable at Donor ASEP 90 % of Non-incremental Obligated Entry (or 80% of Technical IP for IP ASEPs)* *As may be adjusted by paragraph 22c-e Maximum Available Substitutable Sold and/or Reserved capacity Retained quantities See section Retainers for further details release date at recipient ASEP (Usually 42 months) Y+4 Y+5 Y+6 Y+7 Time 1 Following each QSEC auction, or following a PARCA being agreed, 23. demand for Incremental Obligated Entry will be identified. If Incremental Obligated Entry is not released then no further action need be taken by National Grid. If, in accordance with the ECR, National Grid considers that it 24. is appropriate to release Incremental Obligated Entry then the methodology in this Statement shall be applied to see whether the quantity of Incremental Obligated Entry required to be released can be reduced through Entry Substitution. 25. In respect of any QSEC or Annual Yearly auction, capacity will only be considered available for substitution after all qualifying bids for existing capacity have been satisfied, i.e. capacity will be allocated at the ASEP where bids are placed before 812 In the event that incremental capacity is released in advance of the default lead time, it will be necessary, to determine the Substitutable, to consider relevant earlier quarters. Page 15 of 31

being substituted to another ASEP. For the avoidance of doubt in the event that an incremental signal is received and substitution analysis is undertaken prior to the completion of the Annual Yearly auction for an IP ASEP, capacity at that IP ASEP will not be considered as available for substitution. In respect of any PARCA, capacity will only be considered available 26. for reservation pending substitution after all bids for existing unsold capacity placed via the (Ad-hoc) QSEC or Annual Yearly Auction have been satisfied, i.e. capacity will be allocated at the ASEP where bids are placed before being reserved pending substitution to, another ASEP. Notwithstanding paragraph 22.bc), once capacity has been substituted or reserved pending substitution it will not be available to satisfy bids for capacity at that ASEP in future QSEC or Annual Yearly auctions. 913 will only be available to be substituted from an ASEP 27. in the quantity determined in accordance with paragraph 22. 28. Where Entry Substitution is applied the Non-incremental Obligated Entry at the donor ASEP shall be reduced by the quantity, determined in accordance with this Statement, from the date when Incremental Obligated Entry is available for use at the recipient ASEP. In the period prior to this date the capacity will be available to Shipper Users at the donor ASEP. Retainers Shipper Users will be able to exclude capacity at potential donor 29. ASEPs from being treated as Substitutable without having to buy and be allocated the capacity and without having to enter into a PARCA. To do this they will be able to take out a retainer. For the purpose of determining whether a refund of Retention30. Charges is due each retainer is tagged to a specific year. The default year is Y+4, i.e. for a retainer taken out in January 2015 the tagged year is Oct 2018 to Sept 2019. Alternatively a Shipper User may tag their retainer to year Y+5 or Y+6. For a refund to be made capacity must be allocated for the tagged year in accordance with rules defined in the section Retention Charge Refunds of this Statement. If more than one retainer is taken out at an ASEP, within the31. same retainer window, then they shall be aggregated from the tagged year for the purposes of determining the Substitutable, i.e. retainers tagged to year Y+5 shall not be aggregated to Y+4 and retainers tagged to Y+6 shall not be aggregated to Y+4 and Y+5. This is illustrated in Diagram 1. The retainer will be valid for one year commencing 1 st of March 32. of that year, covering all QSEC and Annual Yearly auctions and all PARCAs 1014 held in this period. National Grid will exclude the relevant quantity from the substitution process, but the retainer will not: 913 UNC TPD Section B1.16.42.2.18 includes provisions that provide an option for the initialisation of the Phase 1 PARCA works to be delayed by National Grid until the outcomes / impacts of the annual application process are known. This allows any interactions of the PARCA and Application processes to be assessed and considered on a case by case basis. 1014 The relevant aspect of a PARCA, is the identification, under the Phase 1 PARCA Works, of the possibility (or not) of capacity substitution satisfying the incremental demand, i.e. this activity must fall inside the relevant year for the retainer to have an impact. The date of signature of the PARCA is not relevant. Page 16 of 31

create any rights to the Shipper User to be allocated or to use the capacity. The Shipper User must bid for, and be allocated, capacity in accordance with UNC to obtain any rights over capacity; prevent Shipper Users (including the Shipper User taking out the retainer) from buying that capacity at the ASEP in question in the period covered by the retainer. 33. For the avoidance of doubt, a retainer will prevent capacity a) from being substituted away from an ASEP 15 for any quarter, for which capacity may be released, in any QSEC auction held; and From being reserved pending substitution from an ASEP for b) any quarter, for which capacity may be reserved, pursuant to any PARCA where the relevant substitution analysis work is undertaken; in the year for which the retainer is valid. Retainers will only be available to Shipper Users, i.e. parties 34. who have acceded to the Network Code produced in accordance with Standard Special Condition A11(3) of the Licence. 15 For the avoidance of doubt, in the event that a retainer is taken out at Bacton ASEP in January 2015 and, subject to the implementation of UNC Modification 0501, 0501A, 0501B or 0501C and associated licence changes, this ASEP ceases to operate under the Gas Transporter Licence before the year ends in which the retainer is valid, National Grid will discuss with the Retainer Party which of the new Bacton UKCS and Bacton IP ASEPs the retainer will be applied to for the remainder of the retainer period. Page 17 of 31

Retainer Windows 35. Prior to the annual QSEC and Annual Yearly auction National Grid will open a retainer window allowing Shipper Users to identify the quantity of capacity that they wish to exclude from substitution for specific ASEPs. The retainer window will be open for retainer requests to be submitted 36. on two discrete business days from 8am to 5pm. There will be one business day between the two retainer bid days. The retainer window shall open in the month two months before 37. the month in which both the annual QSEC auction isand Annual Yearly auctions are to be held. No less than 28 days before the first day of the retainer window 38. National Grid shall issue an invitation to Shipper Users to partake in the retainer window. This invitation shall specify, for each ASEP, the maximum available retainer quantity, being the maximum quantity for which retainers may be granted for each of years Y+4, Y+5 and Y+6, i.e. the quantity determined under paragraph 22. Retainers shall be requested via fax using a proforma provided 39. by National Grid. Retainer requests shall be considered as received. Requests40. cannot be removed or amended except where National Grid identifies a blatant error and such removal or amendment is agreed with the Shipper User before 5pm on the day the request is submitted. National Grid shall use reasonable endeavours to provide confirmation of receipt of a retainer request by no later than one hour after the relevant retainer window closes and, where practicable, by no later than one hour before the relevant retainer window closes. On the first day of the retainer window Shipper Users shall be41. able to take out retainers which, in aggregate, when added to the sold capacity shall not exceed the Maximum Available (see Diagram 1). Where Shipper Users request retainers for a greater quantity such requests shall be reduced (in the case of a single Shipper User request) or pro-rated (in the case of multiple Shipper User requests) in proportion to the quantities requested. Retainer requests made on the second day of the retainer window 42. shall be allocated up to a maximum quantity as determined in paragraph 41 minus the retainers granted on the first day. Where reduction or pro-rating of retainer requests is required43. this will be carried out in the sequence Y+4 retainers, then Y+5 and finally Y+6. Retainers shall be rejected where they have no effect on the44. Substitutable ; e.g. where Y+4 retainers plus previously sold capacity are equal to the Maximum Available the Substitutable will be zero. Hence any Y+5 and Y+6 retainers will have no effect and shall be rejected. Provision of Retained Information By 8pm on the day of each retainer window National Grid shall 45. publish on its website, for each ASEP where one or more retainers has been granted, the aggregate quantity covered by those retainers and the adjusted maximum retainer quantity. Page 18 of 31

By 8pm on the day of each retainer window National Grid shall 46. notify individual Shipper Users granted retainers of the relevant ASEPs and quantities. Retention Charges The retainer will be subject to a one-off charge calculated in accordance 47. with the Gas Transmission Transportation Charging Statement and will be payable via an ad-hoc invoice raised within 2 months of the QSEC auction allocations being confirmed; i.e. in July for a March auction. If a Shipper User wishes to protect capacity for more than one year then a further retainer must be obtained each year and a charge will be payable each year for which a further retainer is taken out. Retention Charge Refunds The retainer is intended to ensure that capacity remains at an48. ASEP for Shipper Users to obtain at a later date. In the event that the capacity is not obtained later the retention of capacity may have resulted in unnecessary investment as a result of lost substitution opportunities. Conversely, if capacity is booked at the ASEP where the retainer was taken out, the retainer will have represented genuine future requirements so it is appropriate that the retention charge is refunded in this case. As the retainer ensures that capacity remains at an ASEP for49. any Shipper User to obtain; the retainer does not create any rights over the capacity; the Shipper User granted the retainer shall receive a refund (other than in the circumstances defined in paragraph 53) regardless of which Shipper User is subsequently allocated the retained capacity. Except as defined in paragraph 52 below, for the purposes of 50. triggering refunds the retainer will apply for a default period of 12 months commencing 42 months after the QSEC and Annual Yearly auction that follows the retainer window in which the retainer is granted. 42 months was the default lead-time for the release of Incremental Obligated Entry and hence was, and remains, the earliest time from which substitution can take place. Hence for a refund to apply in respect of a retainer taken out in January 20152016 capacity must, subject to paragraphs 52 and 53, be allocated at the relevant ASEP for at least one month or quarter in the period Oct 20182019 to Sept 2019.2020. Where any capacity covered by a retainer with the default Y+4 51. tag, is allocated to any Shipper User in a QSEC or AMSEC auction, or allocated pursuant to a PARCA, or allocated to any Shipper User in an Annual Yearly or Quarterly Auction, a refund of the retention fee will be made16. For example, for a retainer taken out in January 20152016 would result in a refund where an allocation at the relevant ASEP is made pursuant to QSEC in 2015 11 2016 17, 2016 and 2017, and AMSEC in 2018 and2017 or 2018, or AMSEC in 2019 or 2020. Similarly, a retainer taken out at an IP ASEP in January 2016 would result in a refund where an allocation at the relevant IP ASEP is made pursuant to an Annual Yearly Auction in 2016 17, 2017, 2018 or 2019 or an Annual Quarterly Auction in 2019. Where, in accordance with paragraph 30, a retainer is tagged52. to Y+5 or Y+6, for the purposes of triggering refunds the retainer will apply for a period of 12 months 16 For the avoidance of doubt, where a retainer has been taken out at Bacton ASEP prior to it ceasing to operate under the Gas Transporter Licence, allocations made at the new Bacton UKCS and Bacton IP ASEPs will be taken into account when considering whether a refund should be triggered pursuant to paragraphs 51, 52 and 53. 1117 A refund following the QSEC or Annual Yearly Auction in the year in which a retainer is taken out will be effected by not raising an invoice for the retainer, or by issuing simultaneous invoice and refund. Page 19 of 31

commencing 54 or 66 months (see Diagram 1), respectively, after the QSEC auction that follows the retainer window in which the retainer is granted. Hence for a refund to apply in respect of a Y+6 tagged retainer taken out in January 20152016 capacity must be allocated at the relevant ASEP for at least one quarter in year Y+6 i.e. in the period Oct 20202021 to Sept 2021.2022. Where any capacity covered by a retainer, as defined in paragraph 53. 52 above, is allocated, a refund will only be made if the retained capacity is allocated: In the year the retainer is taken out; to any other Shipper User; (a). In the year following that defined in (a); to the relevant Shipper (b). User; or In the case of a retainer with a Y+6 tag, in the year following (c). that defined in (b); to the relevant Shipper User. Hence for a Y+6 tagged retainer taken out in January 20152016 a refund can only be triggered by: (a). an allocation at the relevant ASEP made pursuant to QSEC in 20152016 (to any other Shipper User), or 2016 and 2017 and 2018 (to the relevant Shipper) User; or (b). an allocation at the relevant IP ASEP made pursuant to the Annual Yearly Auction in 2016 (to any other Shipper User), or 2017 and 2018 (to the relevant Shipper) User; or (c). (b). a PARCA in respect of the relevant ASEP for which capacity allocation takes place in the period (where the PARCA is agreed with any other Shipper User or Reservation Party) March 2015 to February 2016, or (where the PARCA is agreed with the relevant Shipper User) at any. The refund will be calculated annually after the March QSEC54. allocations (taking account, as appropriate, of February AMSEC allocations), or for a retainer taken out at an IP ASEP after the June Annual Quarterly Auctions (taking into account, as appropriate, the March Annual Yearly Auctions), from the difference in the peak allocated quantity for any month or quarter, in the relevant year (see paragraphs 50 and 52) minus the peak allocated quantity for any month or quarter, in the same year, before the retainer is taken out and then comparing this quantity to the retained quantity, if any. Where a full or partial refund is triggered this shall be paid in July following the relevant auction. If only part of the capacity covered by the retainer is allocated55. the refund will be reduced in proportion to the amount allocated. Where more than one Shipper User has been granted a retainer 56. at an ASEP for the same period and some of the retained capacity is allocated, each Shipper User s refund shall be based on the proportion of their retained capacity at the relevant ASEP that has been allocated. Allocations To maximise the potential that capacity covered by a retainer57. is kept at an ASEP for allocation in future auctions, in the QSEC or Annual Yearly auction in the year in which the retainer is granted any unsold capacity that is allocated in respect of any quarter from and including Y+4 will be allocated in the sequence; unprotected capacity first, followed by retained capacity. This is illustrated in Diagram 2, below. Page 20 of 31

Diagram 2: Allocation at ASEPs with Retainers Process for allocation post 42 month default lead-time. E.g. Retainer taken out in Jan 2016. QSEC in Mar 2016 Baseline 90% baseline Unsold at start of auction Withheld from QSEC Retained Quantity Unprotected Existing Sold Post-auction allocations Unprotected capacity will be allocated first, then retained capacity allocated as a result of auction bids Oct 2019 Oct 2020 58. Except where paragraph 57 applies, in all QSEC and, AMSEC and Annual Yearly auctions capacity will be allocated so as to maximise the potential for the refund of retention fees. This recognises that the capacity protected by the retainer was genuinely required even though it was not sold at the time the retainer was requested. In these auctions any unsold capacity that is allocated in respect of any quarter before year Y+4 will be allocated in the sequence; retained capacity first, followed by unprotected capacity. In respect of AMSEC auctions, the 10% withheld from QSEC shall be treated as unprotected. This is illustrated in Diagram 3, below. Where, at any ASEP, retained capacity is allocated, any allocations 59. made in respect of a Shipper User with a retainer at that ASEP will be made against the capacity retained by the same Shipper User as defined by Shipper short codes on Gemini). Hence retainer charge refunds will be targeted towards Shipper Users allocated capacity before those not allocated capacity. Page 21 of 31

Diagram 3: Allocation at ASEPs with Retainers Process for allocation pre 42 month default lead-time. E.g. Retainer taken out in Jan 2016, QSEC in Mar 2017 Baseline 90% baseline Unsold at start of auction Withheld from QSEC Unprotected Retained Quantity Existing Sold Post-auction allocations Retained capacity will be allocated first, then unprotected capacity allocated as a result of auction bids Oct 2019 Oct 2020 Application of Zones Where ASEPs utilise common sections of NTS infrastructure60. and consequently are deemed to be interactive in terms of utilising network capability National Grid will group the ASEPs into zones. Zones shall be used for the identification of potential donor ASEPs due to their interactivity with the recipient ASEP. For all other aspects of this methodology the use of zones is not a mandatory requirement. The zones and the ASEPs that are included in each are provided 61. as Appendix 1 to this Statement. Prior to each retainer window National Grid will publish any revisions to the zones. Recipient ASEP Order Where the QSEC auction and/or any PARCAS results in National 62. Grid identifying the need to release Incremental Obligated Entry at more than one ASEP, analysis of substitution opportunities will be undertaken according to a ranking of recipient ASEPs by their Revenue Driver (RD) 1218 for the first tranche of Incremental Obligated Entry identified (see Special Condition 5F 1319 ). Ranking will start with ASEPs with no RD, followed by the ASEP with the highest RD, then the next highest, and so on, finishing with the ASEP with the lowest RD. The substitution analysis will be assessed in accordance with63. the physical capability of the recipient ASEP local infrastructure. For example, where physical limits exist on the maximum flows that may be achieved from an entry point, no substitution that could take flows above this physical maximum will be allowed. This would also 1218 The adjustment to Totex allowances that results from triggering the incremental capacity uncertainty mechanism is more commonly known as the Revenue Driver. 1319 In the absence of a Generic Revenue Drive Methodology, Revenue Drivers will be determined in accordance with Part D of Special Condition 5G. Where a Generic Revenue Driver Methodology has been approved and applied, the values in Table 6 of Part E shall be used. Page 22 of 31

include the provision of a connecting pipeline from a new system entry point to the existing NTS. Donor ASEP Order All within zone donor ASEPs will be considered before out of64. zone donor ASEPs. Substitutions from individual donor ASEPs will commence by65. reducing the capacity at the most favourable ASEP that has Substitutable and is in the same zone as the recipient ASEP. The most favourable ASEP will be the ASEP providing the lowest exchange rate and is selected in preference to other ASEPs as this will result in the most efficient outcome, i.e. the least aggregate loss of capacity. In the event of two or more donor ASEPs providing equal exchange rates then the donor ASEP will be selected on the basis of nearest ASEP determined according to pipeline distance from the recipient ASEP. Where there is insufficient capacity at the first donor ASEP to66. fully satisfy the Incremental Obligated Entry required at the recipient ASEP the quantity of capacity that can be substituted will be substituted and further within zone ASEPs will be considered in order of most favourable to least favourable exchange rate. Where there is insufficient capacity at all within zone ASEPs 67. to fully satisfy the Incremental Obligated Entry required at the recipient ASEP potential out of zone donor ASEPs will be considered individually on the basis of the most favourable ASEP that has spare capacity. The most favourable ASEP, for out of zone ASEPs, will be the nearest ASEP determined according to pipeline distance. The exchange rate for each donor ASEP, recipient ASEP pairing 68. shall be determined. Where this exceeds 3:1 the substitution shall not be permitted. Substitution at 3:1 and below will be made. Network Analysis for Substitution Potential capacity substitutions shall be validated through network 69. analysis. The objective shall be to avoid incremental increase in risk 1420. Hence National Grid will not propose capacity substitution where this results, under planning scenarios, in the capability of the NTS being reduced below that required. The capacity substitution objective is to minimise investment70. that would otherwise be required to satisfy demand for Incremental Obligated Entry. Substitution opportunities shall be assessed against criteria defined within the Transmission Planning Code which is the basis for National Grid s network development decisions. This shall include existing commitments, including capacities and pressures, on the network. Substitutions shall not be accepted if this puts at risk National Grid s ability to deliver its existing commitments (including capacity reservations pursuant to a PARCA). These commitments will be taken from regulatory and commercial agreements and statutory instruments and are additional to the conditions set out in the National Grid annual planning procedures. The supply and demand scenarios used for the analysis will be 71. consistent with the Transmission Planning Code. 1420 Substitution may affect system capability. National Grid will assess whether a potential substitution would result in an increased risk of a constraint on the network. Page 23 of 31

The analysis shall primarily be undertaken at the peak 1 in 2072. demand level supplemented by analysis for different demand conditions derived from the average load duration curve and be undertaken for a number of gas years starting with the proposed gas year for release of the Incremental Obligated Entry. Substitution Analysis (see Appendix 2) Where an incremental signal has been received analysis is undertaken 73. to determine what capacity exchange would be required to satisfy the incremental capacity request without the need for investment. substitution will be determined by assessing the flow patterns that can be accommodated by the NTS; i.e. without increasing the risk of capacity constraint management actions being required. substitution will firstly be considered within the relevant 74. entry zone. If this cannot satisfy the increment at the recipient ASEP then substitutions outside the relevant entry zone will be considered. Substitution analysis will commence by increasing the flow (in the assessment scenario) at the recipient ASEP to the prevailing Obligated Entry quantity plus any previously reserved capacity. Flow will be reduced at the least interactive ASEP(s) to the recipient 75. ASEP to maintain a supply / demand balance. Substitution analysis will continue by increasing the flow (in the 76. assessment scenario) at the recipient ASEP by the level of the Incremental Obligated Entry. The Obligated Entry will be reduced at the donor 77. ASEP by the incremental quantity at the recipient ASEP. Where the Substitutable at the donor ASEP is less than the incremental capacity then further donor ASEPs will be used. These will be selected according to paragraphs 64-67. Where this impacts on flow, rebalancing will be undertaken at the least interactive ASEP(s) to the recipient ASEP. The Obligated Entry at donor ASEPs will progressively 78. be reduced until either: the Incremental Obligated Entry requirement request is satisfied; or all Substitutable (see paragraph 22) has been substituted; or further capacity cannot be substituted without exceeding an exchange rate of 3:1. In this case the process will move to the assessment of potential substitutions across zones. After all within zone assessments have been completed, i.e. 79. as defined by the above paragraph, any unsatisfied incremental requests will be considered with donor ASEPs from alternative zones. Donor ASEPs will be considered in order of pipeline distance from the recipient ASEP (nearest first). At each stage of the process, e.g. when moving to an additional 80. donor ASEP the individual donor ASEP to recipient ASEP exchange rate will be determined. All substitutions shall be subject to a limit on the maximum permitted 81. exchange rate of 3:1. This means that where analysis shows that more than 3 units of capacity are required from a donor ASEP to create 1 unit at the recipient ASEP then the Page 24 of 31